1. Field of the Invention
This invention is concerned with novel acidic polyesters and with water-based coatings containing them and an aminoplast.
2. Description of the Prior Art
In U.S. Pat. No. 3,046,252 there is described a polyester having a relatively low acid number and hydroxyl number, which is produced by the condensation reaction of benzene tricarboxylic acids with an alkylene oxide or an alkylene glycol. Coatings are formed with these polyesters and an aminoplast in vehicles conventionally used for alkyd resins, such as aromatic hydrocarbons. If a water-soluble baking resin is desired, these polyesters must be converted to salts by reaction with an alkaline agent.
The acidic polyester resins of the present invention of relatively high acid numbers and hydroxyl numbers are readily soluble in aqueous vehicles without resort to salt-forming. Insofar as is now known, acid polyester resins of this type have not been described heretofore.